Manual

214 • Calibrating and Bump Testing the PPM Combustible Sensor Gas Tracer Op-
tube and open the clamp allowing the instrument to draw zero air
for 2 minutes.
6. Hold down the AIR▲ button. The unit will prompt you to continue
holding the AIR▲ button.
7. When the unit prompts you to release the AIR▲ button, release it.
The instrument will perform a fresh air adjustment on the ppm
sensor and return you to the AIR CAL menu item. If a gas bag with
zero air was used, disconnect the humidifier from the probe.
NOTE: Grasp the humidifier tube assembly by the clear tubing at the
end, not the humidifier tube itself.
Performing a Dry Fresh Air Adjustment
This section describes how to perform a fresh air adjustment on the
PPM combustible gas sensor using the DRY setting. Use the DRY
setting with a zero air calibration cylinder for a biannual calibration.
NOTE: It is recommended that you perform a fresh air adjust on the
ppm sensor using a zero air cylinder and the DRY setting
followed by a fresh air adjustment using the WET setting once
every 6 months to maintain the accuracy of the ppm
combustible gas reading. See “Performing a Wet Fresh Air
Adjustment” on page 212 for instructions to perform a WET
fresh air adjustment.
AIr
CAL
MAINTENANCE
HOLD AIR